Though it’s impossible to know the weight of a stare, scientists now have a good idea of its crushing force : in particular, on women who think they’re being sexually objectified.

In experiments with more than 200 people, researchers discovered that when a female believes her body is being sized up by a male, she’ll diminish her presence by speaking less. When a male believes a female is eyeing his physique, however, no such effect occurs.

The study, published this month in the journal Psychological Science, explains that our culture has so taught women that they’re judged on appearance that they’ve come to evaluate themselves that way, ultimately self-objectifying.

“Women actually become object-like in that they stop talking and expressing themselves,” says study co-author Diane Quinn, associate professor of psychology at the University of Connecticut.

Study participants were given two minutes to introduce themselves via closed-circuit camera to an unseen partner, with researchers explaining that they’d be filmed in one of three conditions: audio only, from the neck up, or from the neck down, and all under the pretext of a communication exercise that examined social interaction through the lens of facial expressions, body gestures and vocal cues.

In the body-focused condition, women talked, on average, for just 84.9 seconds when they thought their partner was male, but for the near-full 111.9 seconds when told their partner was female. Researchers note that this shows “it was a male’s gaze, and not simply any gaze, that affected women’s presence.”

By contrast, men subjected to having their bodies filmed reduced their talk-time, on average, by just one second : from 117.8 to 116.8 : when they thought their partner was of the opposite sex.

The results of the full study are described in the paper by Tamar Saguy, Diane M. Quinn, John F. Dovidio and Felicia Pratto, “Interacting Like a Body: Objectification Can Lead Women to Narrow Their Presence in Social Interactions.” The paper is available here in PDF.